Non-reversal imaging process and recording elements produced thereby

ABSTRACT

A non-reversal imaging process wherein a recording element having a layer of a photosensitive composition which upon light exposure produces light-generated nuclei of a metal more noble than silver, i.e. Pd, Pt, Au, is exposed to an image. The exposed element is treated with a solution of trimethylamine borane, triethylamine borane, t-butylamine borane, pyridine borane, morpholine borane, sodium borohydride, lithium aluminum hydride or hydrazine to generate in the unexposed areas of the layer chemically reduced metal nuclei which are more highly catalytic to the electroless deposition of a non-noble metal than the light generated nuclei. Non-noble metal is then electrolessly plated selectively on the chemically reduced nuclei to produce a nonreversed image.

United States Patent Miller [72] Inventor: Richard A. Miller, White Bear Lake,

Minn.

Minnesota. Mining and Manufacturing Company, Saint Paul, Minn.

[22] Filed: July 19,1968

[2]] Appl. No.: 745,976

[73] Assignee:

[52] US. Cl, ..96/48 PD, 96/362, 117/130 E [51] Int. Cl. ..G03c 5/24 [58] Field of Search ..96/48 PD, 49; 117/130 E, 130 B [56] References Cited UNITED STATES PATENTS 2,267,953 12/ 1941 Schumpelt ..96/49 2,690,402 9/1954 Crehan ..l17/47 2,990,296 6/1961 l-loke ..1 17/130 B 3,446,621 5/1969 Hackmann et al ..96/49 [151 3,65,95 [4 1 Apr. 1, 1972 OTHER PUBLICATIONS Jonker et al., Physical Development Recording Systems, Photographic Sci. & Eng. Vol. 13, Nos. 1 & 2 (1969) Primary Examiner-Norman G. Torchin Assistant Examiner-John Winkelman Attorney-Kinney, Alexander, Sell, Steldt & Delahunt [57] ABSTRACT A non-reversal imaging process wherein a recording element having a layer of a photosensitive composition which upon light exposure produces light-generated nuclei of a metal more noble than silver, i.e. Pd, Pt, Au, is exposed to an image. The exposed element is treated with a solution of trimethylamine borane, triethylamine borane, t-butylamine borane, pyridine borane, morpholine borane, sodium borohydride. lithium aluminum hydride or hydrazine to generate in the unexposed areas of the layer chemically reduced metal nuclei which are more highly catalytic to the electroless deposition of a non-noble metal than the light generated nuclei. Non-noble metal is then electrolessly plated selectively on the chemically reduced nuclei to produce a nonreversed image.

14 Claims, No Drawings NON-REVERSAL IMAGING PROCESS AND RECORDING ELEMENTS PRODUCED THEREBY This invention relates to a non-reversal imaging process and unreversed image-containing recording elements produced thereby.

Direct unreversed image reproductions have been obtained by several known methods, such as diazo processes, vesicular processes and processes involving the use of light-sensitive silver halide materials. In a common diazo process, a diazonium salt contained within a photographic element undergoes decomposition in light-exposed areas of the element upon exposure to a light image. The diazonium salt in non-exposed areas of the element is thereafter converted to an azo dye by reacting with an azo coupling compound, producing an unreversed image. A vesicular process utilizes a photographic element containing a compound which evolves vapor slowly upon exposure to light and which evolves vapor rapidly upon heating. Upon exposure to a light image, vapor evolved in exposed areas escapes by diffusion. Thereafter, upon heating, vapor is rapidly evolved in non-exposed areas of the photographic element to form small, light-scattering bubbles therein. f the many silver halide processes, one silver halide process involves exposing a photographic element to a light image to form metallic silver nuclei in light-exposed areas, developing the element to form a metallic silver image, oxidizing and dissolving away the metallic silver, and exposing and developing the silver halide remaining in non-exposed areas to yield an unreversed image. Another silver halide process involves the formation of the usual metallic silver image by exposure of a photographic element to a light image. The silver halide contained in non-light-struck areas of the element diffuses into an adjacent receptive layer whereupon reduction of this silver halide to metallic silver occurs to form an unreversed image.

Such processes are often laborious, time-consuming and expensive, and produce images which often lack good definition and high contrastlmages generally are contained within the layers of a photographic element, rather than on the surface thereof. The production 'of products therefrom which are dependent upon surface properties (e.g., printed circuits) is hence difficult or impossible.

An object of the present invention is to provide a non-reversal'imaging process whichyields unreversed image reproductions of high resolution and contrast.

Another object is to provide a non-reversal imaging process which requires very small amounts of precious metals.

Another object is to provide a recording element bearing on its surface an unreversed metallic image of a non-noble'metal.

Yet another object is to provide a simple and inexpensive nonreversal imaging process.

Briefly, the present inventionrelates'to a non-reversal imaging process comprising thefollowing steps:

1. exposing to a light image a recording element having a photosensitive layer'comprising a composition capable, upon light exposure, of reducing compounds of metals more noble than silver to nuclei of said metals;

2. providinginsaid'photosensitive layer a compound of a metal more noble than silver, "thereby generating said metal nuclei in light-exposed areas of said element;

3. treating said photosensitive layer with a solution of trimethylamine borane, triethylamine borane, dimethylamine borane, diethylamine borane, t-bu- 'tylamine borane, pyridine borane, morpholine borane, sodium borohydride, lithium aluminum hydride, or hydrazine to cause generation selectively in non-light-exsteps l) and (2) are carried out simultaneously to form metal nuclei in light-exposed areas of the photosensitive layer. However, the photosensitive layer may be contacted with the noble metal compound after light exposure, if desired, by merely applying a solution containing said noble metal compound on the surface of the photosensitive layer. Further, steps (3) and (4) preferably are performed by treating the exposed recording element of step (2) with the solution of step (3) in which is dissolved a salt of a non-noble metal such as nickel or cobalt. Because lithium aluminum hydride reacts violently with water, this compound must not be incorporated in an aqueous electroless plating bath.

posed areas of said photosensitive layer of chemically reduced nuclei of said metal; and 4. plating non-noble metal differentially on said chemically reduced metal nuclei by electroless deposition. 'Preferably, the photosensitive layer of the recording element initially (i.e. before light exposure) comprises both the composition of step l) and the noble metal compound of step (2)so that, upon exposure of the element to a light image,

For brevity, reducing compounds of the class comprising trimethylamine borane, triethylamine borane, dimethylamine borane, t-butylamine borane, pyridine borane, morpholine borane, sodium borohydride, lithium aluminum hydride and hydrazine are hereafter referred to as graphic-positive reducing agents. Of these reducing agents, dimethylamine borane is preferred.

This invention further relates to a recording element comprising a layer having light-exposed areas and non-light-exposed areas, said layer having light-generated nuclei of a metal more noble than silver selectively in said light-exposed areas and having chemically reduced nuclei of said metal more noble than silver selectively in said non-light-exposed areas, the chemically reduced nuclei being more highly catalytic to the electroless deposition of a non-noble metal than are the light-generated metal nuclei. Said chemically reduced nuclei may in addition bear a deposit of a non-noble metal, which non-noble metal may be electrically conductive.

Light-generated metal nuclei as used herein refer to nuclei generated on a recording element by exposure of the element to light, which nuclei may be catalytic to the electroless deposition thereon of a non-noble metal.

Chemically reduced metal nuclei" as used herein refers to nuclei which are generated in non-light-exposed areas of a recording element by treating the photosensitive layer thereof with a graphic-positive reducing agent, which nuclei are more highly catalytic to the electroless deposition of a non-noble metal than are light-generated m'etal nuclei.

U.S. Pat. application Ser. No. 644,792 teaches a method for producing reversed (negative) images on photographic elements similar to those of the present invention by an electroless plating technique. Various electroless plating procedures are illustrated by U.S. Pat. Nos. 3,338,726; 2,532,284; 2,690,401; 2,690,402; 2,726,969; 2,762,723; 2,87l,l42 and 3,011,920. The use of amine borane compounds in photographic silver halide emulsions has been described in U.S. Pat. No. 3,361,564. The electroless deposition of metals involves the simultaneous reduction of metal ions and oxidation of a reducing agent on catalytic surfaces, resulting in the deposition of free metal atoms on the catalytic surfaces. It is surprising that one obtains unreversed images by the processes of the present invention since a reversed image, if any, would be expected.

Although the processes of the present invention preferably are utilized in the production of half-tone unreversed image reproductions, continuous-tone reproductions can be produced by carefully regulating the quantity of exposing radiation in step 1 (above).

The mechanism by which the non-reversed images of the present invention are formed is not completely understood. It is believed, however, that light-generated metal nuclei are fonned in light-struck areas of recording elements of the present invention upon exposure of such elements to a light image. These nuclei apparently decrease the quantity of chemically reduced nuclei which can be formed in light-struck areas of such elements, and chemically reduced nuclei hence are selectively developed in non-light-struck areas of the element. Stated in other terms, the quantity of chemically reduced nuclei is inversely proportional to light intensity. A significant feature of this invention is the discovery that chemically reduced nuclei are more highly catalytic to the electroless deposition of non-noble metals than are lightgenerated nuclei. Accordingly, upon treatment with an electroless plating solution, the areas of the recording element bearing the chemically reduced nuclei, i.e. the unexposed areas, can be more rapidly plated with non-noble metal to form a non-reversed image.

The nuclei of the present invention are reduced forms of the noble metal compounds contained within photosensitive layers of recording elements of the present invention. It is believed that such nuclei are free metal nuclei of these noble metal compounds.

An important part of this invention is the discovery that compounds of metals more noble than silver which, in combination with photosensitive compounds, undergo reduction to metal nuclei upon light exposure, also provide chemically reduced metal nuclei upon treatment with solutions of graphic-positive reducing agents, and that the chemically reduced nuclei are more highly catalytic to the deposition thereon of a non-noble metal than are the light-generated nuclei.

Light-sensitive compositions capable of producing catalytic nuclei of metals more noble than silver upon light exposure commonly contain noble metal compounds in the form of metal salts, such as palladium (II) chloride and platinum (IV) chloride, etc., or of complexed metallic compounds, such as the complexes of palladium I1 and platinum IV with ethylenedinitrilotetraacetic acid, nitrilotriacetic acid and trans-l,2-diaminocyclohexanetetraacetic acid. Some of these metal compounds are autogenously photonucleating. However, because of the slow rate of reaction associated with autogenic photonucleation, light-sensitive compositions preferably further contain light-sensitive compounds which, upon exposure to light, are capable of reducing the noble metal compounds to nuclei of said noble metal compounds. Examples of preferred light-sensitive compounds include certain iron IlI compounds, such as ferric ammonium oxalate, ferric ammonium citrate, etc., and certain diazosulfonate compounds such as sodium o-methoxybenzenediazosulfonate, sodium 4-chloro-2,5-dimethoxybenzenediazosulfonate, etc.

Iron Ill compounds are primarily sensitive to ultra-violet light. Diazosulfonate compounds are sensitive not only to ultraviolet light but also to visible light, and hence are preferred in the present invention.

Photographic elements useful in the present invention preferably are produced by thinly coating upon the hydrophilic surface of a supporting substrate an aqueous solution comprising a compound of a metal more noble than silver, a compound capable, upon light exposure, of-reducing said compound of a metal more noble than silver to metallic nuclei, if required, and commonly-used photographic coating aids such as polymeric binders, wetting agents, etc. The substrate is preferably a transparent polymeric film such as polyester, cellulose triacetate, etc., which has been treated to provide a hydrophilic surface upon which the above solution may more readily be coated. However, many other substrates can be utilized, such as paper, glass, cloth, wood, metal, etc.

Obtaining a suitable substrate surface is important to the proper operation of the present invention. Since the photosensitive layer or layers coated thereon are relatively thin, care must be taken to prevent the loss of catalytic nuclei, especially the chemically reduced nuclei, during subsequent processing. The surface of cellulose triacetate film saponified with a sodium hydroxide-ethanolwater solution has been found useful. A preferred substrate results from the application of a methyl vinyl ether maleic anhydride copolymer solution to polyester film, followed by treatment with a basic amine solution. This copolymer is commercially available as Gantrez AN-l 39 (a trademarked product of General Aniline & Film Corporation) and the use thereof is described in U.S. Pat. No. 2,756,163 issued on July 24, 1956 to General Aniline & Film Corporation.

Examples of non-noble metal compounds which are useful in the electroless plating solutions of the present invention include compounds of nickel, cobalt, copper, chromium, and

iron. Salts of nickel and cobalt are especially preferred because of the dense, black images they provide.

Electroless plating solutions containing graphic-positive reducing agents commonly exhibit a water-like viscosity. The 5 viscosity can be increased by a number of methods, such as by adding a gelling agent or a soluble polymer to the solution. Such viscous solutions may be advantageously used in obvious modifications of the process of the present invention, for example, wherein the viscous solution is contained in a separate sheet adapted to contact the photographic element following light exposure, or wherein the viscous solution is contained within a container adapted to spread the solution upon the photographic element following light exposure.

The following examples are presented for illustrative purposes only, and should not be construed as limiting the scope of the present invention.

EXAMPLE 1 A photosensitive coating solution was prepared as follows:

Palladium Chloride (0.1 g.) and concentrated hydrochloric acid (0.4 ml.) were dissolved in water to form 50 ml. of a homogeneous solution. To this solution was added 1.0 g. of ethylenedinitrilotetraacetic acid disodium salt dihydrate, which, upon dissolving in the solution, caused formation of a white precipitate. The precipitate was redissolved by the addition of sufficient ammonium hydroxide to yield a solution of pH 3.5-4.0. Polyvinylpyrrolidone (PVP K-90, General Aniline and Film Corporation) (4.0 g.) and Tinegal NA (a polyoxyethylated fatty alcohol, Giegy Chemical Company) (0.5 g.) were dissolved in the solution which was then filtered and diluted with water to a volume of 200 ml. 1n subdued light, 2.0 g. of ferric ammonium oxalate were dissolved in the solution.

A sheet of surface-saponified cellulose triacetate film was prepared by immersing a sheet of cellulose triacetate forthree minutes in a solution of 1,180 ml. aqueous 35 percent sodium hydroxide solution,

1,640 ml. 95 percent ethanol,

24 ml. Igepal CO-630 (an alkylphenoxy-poly[ethyleneoxy] ethanol, General Aniline and Film Corp.), and

940 ml. water; and then immersing the sheet in a 2 percent aqueous acetic acid solution for one minute. The sheet was washed with water for five minutes and dried in air at room temperature.

The photosensitive coating solution was then poured onto one surface of the surface-saponified cellulose triacetate film. The sheet was drained of excess solution and was dried by exposure to mild radiant heat to form light-sensitive photographic element.

An electroless plating bath containing 1,000 ml. water,

20 g. nickel chloride hexahydrate, 10 g. cobalt chloride hexahydrate, 100 g. potassium sodium tartrate, 25 g. ammonium hydroxide,

12 g. glycine, and

10 g. sodium dihydrogen phosphite was prepared, the pH of which was adjusted to 9.0 by addition of a small amount of sodium hydroxide.

The photographic element was exposed for four minutes through a transparent line original to radiation from a 275- watt General Electric Sunlamp (rich in U.V. radiation) positioned 25.4 cm. from the coated surface of the photographic element. Thereafter the element was agitated for 20 seconds in a 0.1 percent w/w aqueous dimethylamine borane solution which had been adjusted to pH 6.5 by addition of acetic acid and ammonium hydroxide. The exposed photographic element was then immersed in the above electroless plating bath at 80 C. for 30 seconds. An unreversed reproduction of the line original was obtained, having a dense black image upon a clear background.

An unexposed photographic element identical to that of Example l was prepared. After exposure through a transparent line original for minutes to radiation from a 275-watt General Electric Sunlamp at a distance of 25.4 cm., the photographic element was immersed for 60 seconds at 50 C. in an electroless plating bath containing a graphic-positive compound, which bath was prepared as follows:

To 800 ml. of water were added 40 g. of nickel sulfate hexahydrate and 40 g. of lactic acid. The solution pH was adjusted to 6.5 with ammonium hydroxide. To this solution was added a solution of 2.0 g. of dimethylamine borane (the graphicpositive compound) in 40 ml. of water, followed by the addition of 1.0 ml. of a percent aqueous solution of lgepal CO-630. The total solution volume was adjusted to 1,000 ml. with water.

After immersion, the photographic element was washed with water and dried in air at room temperature. A high-contrast unreversed reproduction of the line original was obtained which exhibited a rich, deep black image on a clear background.

EXAMPLE 3 in red safelight, a photosensitive coating solution identical to that of Example 1 was prepared except that 2.0 g. of sodium o-methoxybenzenediazosulfonate was used in place of the ferric ammonium oxalate. A photographic element was formed by coating this solution on the surface of a saponified cellulose triacetate sheet which was prepared by the procedure of Ex ample 1.

After drying with radiant heat, the photographic element was exposed through a transparent line original to radiation from a ISO-watt incandescent reflector spot lamp (rich in visible light) for 2 seconds, the lamp being positioned 46 cm. from the surface of the photographic element.

An electroless plating bath identical to that of Example 2 was prepared, except that 40 g. of nickel chloride hexahydrate was substituted for the nickel sulfate hexahydrate. The exposed photographic element was immersed in this bath for one minute at 46 C. An unreversed photographic reproduction of the line original having considerable background fog was obtained. When the period of light exposure was increased from two seconds to twenty seconds, a unreversed reproduction was obtained which exhibited no background fog.

EXAMPLE 4 Photographically subbed polyester film (type M4lD subbing of Bexford, Ltd. on Melinex polyester film, Imperial Chemical Industries) was knife-coated to a wet thickness of 0.05 mm. with a solution of 6 g. Gantrez AN-l39 copolymer (General Aniline & Film Corp.) 14 g. Cellulose propionate (Celanese Corp. Type HLFS-70) 200 ml. methyl ethyl ketone, and

25 ml. cyclohexanone and was dried thoroughly. The film surface was rendered hydrophilic by immersion in a 0.1 percent aqueous ethanolamine solution for 4 minutes, followed by water washing and air drying.

The film was coated with the photosensitive coating solution of Example 3, dried by radiant heat, and exposed for one minute through a transparent line original to radiation from a l50-watt incandescent spot lamp at a distance of 46 cm.

The photographic element was then immersed in the electroless plating bath of Example 3 for 2 minutes, and was subsequently washed with water and blotted dry. A high-contrast unreversed reproduction of the line original was obtained.

EXAMPLE 5 The unexposed photographic element of Example 3 was exposed for 2 minutes through a line-negative to radiation from a ISO-watt incandescent reflector spot lamp at a distance of 76 cm. The exposed photographic element was cut into three samples, one of which was immersed in the plating bath of Example 2 at a temperature of 21 C., the second of which was immersed in an identical bath at 49 C., and the third of which was immersed in an identical bath at 82 C. The immersion periods required to produce similar high contrast, unreversed line image reproductions upon the three samples were 8 minutes, 2 minutes and 20 seconds, respectively.

EXAMPLE 6 A photographic element identical to the element of Example 2 was exposed through a line-negative to radiation from a 275-watt General Electric Sunlamp at a distance of 30.5 cm. for 5 minutes.

An electroless plating solution was prepared by adding 20 g. of nickel chloride hexahydrate and 20 g. of lactic acid to a homogeneous solution of hydrolyzed Gantrez AN-l39 polymer (50 g.) in 350 ml. of water. After adjustment of the solution pH to 6.5 by the addition of ammonium hydroxide, the solution was found to be very viscous, exhibiting a viscosity of about 28,000 cp. To this solution was added a solution of 1.0 g. of dimethylamine borane in 25 ml. of water, followed by 5 drops of a 10 percent aqueous Igepal CO-630 solution. The total solution volume was then adjusted to 500 ml. with water.

A thick layer of this viscous plating solution was applied to the exposed surface of the photographic element which was then heated to a temperature of about 40 C. for 4 minutes. After removal of excess plating solution, the photographic element was dried without further processing to yield an unreversed image reproduction with no background fog.

EXAMPLE 7 A sample printed circuit was prepared as follows:

A photographically subbed polyester film of the type described in Example 4 was thinly coated with the photosensitive coating solution of Example 1, dried, and exposed through a line-negative for 5 minutes to radiation from a 275- watt General Electric Sunlamp at a distance of 30.5 cm. After immersion in the electroless plating bath of Example 2 for one minute, followed by washing with water and air-drying, a bright, metallic, unreversed image reproduction was obtained.

The copper plating bath shown in US. Pat. No. 3,310,430 was prepared as follows: To 30 g. of copper sulfate pentahydrate dissolved in 1,800 ml. of water was added 80 g of ethylenedinitrilotetraacetic acid disodium salt. The pH of the resulting solution was increased to 12 by addition of 25 percent aqueous sodium hydroxide solution. 12 ml. of formalin, 2.0 ml. of 0.5 percent aqueous sodium vanadate solution (prepared by dissolving sodium metavanadate in dilute sodium hydroxide solution) and 2.0 ml. of 10 percent aqueous Igepal CO-63O solution were added, and the solution volume was diluted to 2 liters with water.

The unreversed image reproduction obtained above was immersed in the copper plating bath for two hours at 60 C. A bright, electrically-conductive copper deposit was fon-ned on the unreversed nickel image to yield a printed circuit useful in electronic devices.

EXAMPLE 8 An unexposed photographic element identical to that of Example 3 was prepared, except that the-polyvinylpyrrolidone component was omitted from the coating solution. After exposure for two minutes through a line-negative to radiation from a ISO-watt reflector incandescent spot lamp at a distance of 76 cm., the photographic element was immersed in the bath of Example 3 for 1 minute at 50-53 C. A high-contrast, unreversed image reproduction was obtained.

EXAMPLE 9 An unexposed photographic element identical to that of Example 3 was prepared except that the polyvinylpyrrolidone component was replaced with 2.0 g. of polyvinyl alcohol (Gelvatol 20-30, Monsanto Chemical Company) in the photosensitive coating solution. Upon exposure and processing as in Example 8, a high-contrast, unreversed image reproduction was obtained.

EXAMPLE 10 Example 9 was duplicated except that the poly vinyl alcohol component of the photosensitive coating solution was replaced with 2.0 g. of polyethylene glycol 6,000 (Matheson, Coleman and Bell Chemical Company). A high-contrast, unreversed image reproduction similar to that of Example 9 was obtained.

EXAMPLE 1 1 A photosensitive coating solution was prepared as follows:

Palladium chloride (0.2 g.)

conc. hydrochloric acid (0.8 ml.),

Igepal CO-630 (1.0 g.), and

polyvinyl pyrrolidone (PKP-K90) (8.0 g.) were dissolved in water to form 400 ml. of solution, to which was then added 4.0 g. of ferric ammonium oxalate trihydrate. This solution was poured onto one surface of a saponified cellulose triacetate film which had been prepared by the procedure of Example 1. The film was drained of excess solution and was dried by exposure to mild radiant heat to form a photosensitive photographic element.

The element was exposed through a line negative to radiation from a 275-watt sunlamp (General Electric Corporation) at a distance of 25.4 cm. for 4 minutes. The exposed element was immersed for 30 seconds in a solution of the graphic-positive compound trimethylamine borane, the solution consisting of 0.5 g. trimethylamine borane,

20 ml. 95 percent ethyl alcohol, and

180 ml. water.

After rinsing with water, the element was immersed for 30 seconds in the electroless plating bath of Example 1 at 80 C.

Upon drying, the photographic element exhibited an unreversed reproduction of the original line negative.

EXAMPLES 12-18 Example 11 was duplicated using solutions of different graphic-positive compounds and with various periods of immersion in these solutions. In each example, an unreversed image reproduction of the line negative was obtained.

Example Graphic-Positive Reducing Agent lmmersion Time 12 Sodium borohydride, 0.5% solution in 30 seconds water, raised to pH 12 with cone. NaOH.

l3 Morphcline borane, 0.5 g. in 20 ml. 30 seconds 95% ethyl alcohol and 180 ml. water.

[4 Pyridine borane, 0.5 g. in 20 ml. 30 seconds 95% ethyl alcohol and 180 ml. water.

15 t-Butylamine borane, 0.5 g. in ml. seconds 95% ethyl alcohol and 180 ml. water.

16 Triethylamine borane, 0.5 g. in 20 ml. 30 seconds 95% ethyl alcohol and 180 ml. water.

l7 Lithium aluminum hydride, 1.0 g. in 1 minute 200 ml. ethyl ether.

l8 Hydrazine, 0.25% (w/w) in absolute 2 minutes ethyl alcohol.

EXAMPLE 19 A sheet of cellulose triacetate, saponified as in Example 1, was coated with a solution of 0.5 g. ferric ammonium oxalate, 1 drop Tinegal NA and 50 ml. of water. After drying, the sheet was exposed through a transparent line original to radiation from a 275-watt sunlamp (General Electric Corporation) at a distance of 25.4 cm. for 8 minutes.

The exposed surface of this sheet was then sprayed with a fine mist of a solution consisting of ml. of water and 10 ml. of the photosensitive coating solution of Example 1 (omitting the ferric ammonium oxalate) from a perfume atomizer to form a perceptibly wet coating on the sheet. The sheet was then dried with radiant heat and immersed in the electroless plating bath of Example 3 for 2 minutes at 50 C. An unreversed reproduction of the line original was obtained.

EXAMPLE 20 A sheet of cellulose triacetate, saponified as in Example 1, was coated with a 1 percent w/w aqueous solution of sodium o-methoxybenzenediazosulfonate, dried, and exposed for 2 minutes through a transparent line original to radiation at an intensity of 3,200 foot-candles from a tungsten lamp. The exposed surface of this sheet was sprayed with a fine mist of the photosensitive coating solution of Example 1 (omitting the ferric ammonium oxalate component) from a perfume atomizer and was dried with radiant heat. The sheet was immersed in the electroless plating bath of Example 3 at 55 C. for 1 minute. An unreversed reproduction of the line original was obtained.

What is claimed is:

1. A recording element comprising a layer having light-exposed areas and non-light-exposed areas, said layer having light-generated nuclei of a metal more noble than silver selectively in said light-exposed areas and having chemically reduced nuclei of said metal more noble than silver selectively in said non-light-exposed areas, said layer additionally having a first non-noble metal selectively electrolessly deposited on said chemically reduced nuclei.

2. The recording element of claim 1 wherein said noble metal is palladium or platinum.

3. The recording element of claim 1 wherein said noble metal is palladium or platinum and wherein said first nonnoble metal is cobalt or nickel.

4. The recording element of claim 1 wherein said non-noble metal deposit is electrically conductive.

5. The recording element of claim 1 additionally comprising a second non-noble metal electrolessly deposited upon said first non-noble metal deposit, said second non-noble metal deposit being electrically conductive.

6. The recording element of claim 5 wherein said second non-noble metal is copper.

7. A recording element comprising a layer having light-exposed areas and non-light-exposed areas, said layer having light-generated nuclei of a metal more noble than silver selectively in said light-exposed areas and having chemically reduced nuclei of said metal more noble than silver selectively in non-light-exposed areas, said chemically reduced nuclei being more highly catalytic to the electroless deposition of a non-noble metal than are said light-generated nuclei, said layer additionally having a non-noble metal selectively electrolessly deposited on said chemically reduced nuclei.

8. A recording element comprising a layer having light-exposed areas and non-light-exposed areas, said layer having light-generated nuclei of a metal more noble than silver selectively in said light-exposed areas and having in non-light-exposed areas chemically reduced nuclei resulting from the treatment of said layer with a solution of trimethylamine borane, triethylamine borane, dimethylamine borane, diethylamine borane, t-butylamine borane, pyridine borane, morpholine borane, sodium borohydride, lithium aluminum hydride or hydrazine, said chemically reduced nuclei being more highly catalytic to the electroless deposition of a nonnoble metal than are said light-generated metal nuclei, said layer additionally having a deposit of a non-noble metal selectively superimposed on said chemically reduced nuclei.

9. A non-reversal imaging process comprising the sequential steps of a. exposing to a light image an element having a photosensitive layer comprising a composition capable, upon light exposure, of reducing compounds of metals more noble than silver to nuclei of said metals;

b. providing in said photosensitive layer a compound of a metal more noble than silver, thereby producing light generated nuclei of said metal in light-exposed areas of said photographic element;

c. treating said element with a solution of trimethylamine borane, triethylamine borane, dimethylamine borane, diethylamine borane, t-butylamine borane, pyridine borane, morpholine borane, sodium borohydride, lithium aluminum hydride or hydrazine to cause generation selectively in the non-light-exposed areas of said photographic element of chemically reduced nuclei of said metal; and

d. plating non-noble metal differentially on said chemically reduced metal nuclei by electroless deposition.

10. The process of claim 9 wherein said non-noble metal is cobalt, nickel or copper.

11. A non-reversal imaging process comprising the subsequential steps of a. exposing to a light image a recording element having a photosensitive layer comprising a composition which upon light exposure is capable of producing nuclei of metal more noble than silver;

b. treating said photosensitive layer with a solution of trimethylamine borane, triethylamine borane, dimethylamine borane, diethylamine borane, t-butylamine borane, pyridineborane, morpholine borane, sodium borohydride, lithium aluminum hydride, or hydrazine to cause generation selectively in non-light exposed areas of chemically reduced metal nuclei of said noble metal; and

c. plating non-noble metal differentially on said chemically reduced metal nuclei by electroless deposition.

12. A non-reversal imaging process comprising the sequential steps of a. exposing to a light image a recording element having a photosensitive layer comprising a composition which, upon light exposure, is capable of producing nuclei of platinum or palladium;

b. treating said photosensitive layer with a solution of trimethylamine borane, triethylamine borane, dimethylamine borane, diethylamine borane, t-butylamine borane, pyridineborane, morpholine borane, sodium borohydride, lithium aluminum hydride, or hydrazine to cause generation selectively in non-light-exposed areas of chemically reduced nuclei of platinum or palladium; and

c. plating non-noble metal differentially on said chemically reduced nuclei by electroless deposition.

13. A non-reversal imaging process comprising the sequential steps of a. exposing to a light image a recording element having a photosensitive layer comprising a composition which upon light exposure is capable of producing nuclei of a metal more noble than silver, and

b. treating said photosensitive layer with a solution of a nonnoble metal compound and trimethylamine borane, triethylamine borane, dimethylamine borane, diethylamine borane, t-butylamine borane, pyridine borane, morpholine borane, sodium borohydride, or hydrazine to cause generation selectively in non-light-exposed areas of said photographic element of chemically reduced metal nuclei of said noble metal and to plate said non-noble metal differentially on said chemically reduced metal nuclei by electroless deposition.

14. A non-reversal imaging process comprising the sequential steps of a. exposing to a light image a recording element comprising a photosensitive layer having a composition which upon light exposure is capable of generating nuclei of platinum or palladium; and

b. treating said exposed photosensitive layer with an aqueous dimethylamine borane solution having, as a component, a compound of nickel or cobalt to cause development of chemically reduced nuclei of platinum or palladium in non-light exposed areas of said photosensitive layer and to deposit nickel or cobalt differentially on said chemically reduced nuclei by electroless deposition. 

2. The recording element of claim 1 wherein said noble metal is palladium or platinum.
 3. The recording element of claim 1 wherein said noble metal is palladium or platinum and wherein said first non-noble metal is cobalt or nickel.
 4. The recording element of claim 1 wherein said non-noble metal deposit is electrically conductive.
 5. The recording element of claim 1 additionally comprising a sEcond non-noble metal electrolessly deposited upon said first non-noble metal deposit, said second non-noble metal deposit being electrically conductive.
 6. The recording element of claim 5 wherein said second non-noble metal is copper.
 7. A recording element comprising a layer having light-exposed areas and non-light-exposed areas, said layer having light-generated nuclei of a metal more noble than silver selectively in said light-exposed areas and having chemically reduced nuclei of said metal more noble than silver selectively in non-light-exposed areas, said chemically reduced nuclei being more highly catalytic to the electroless deposition of a non-noble metal than are said light-generated nuclei, said layer additionally having a non-noble metal selectively electrolessly deposited on said chemically reduced nuclei.
 8. A recording element comprising a layer having light-exposed areas and non-light-exposed areas, said layer having light-generated nuclei of a metal more noble than silver selectively in said light-exposed areas and having in non-light-exposed areas chemically reduced nuclei resulting from the treatment of said layer with a solution of trimethylamine borane, triethylamine borane, dimethylamine borane, diethylamine borane, t-butylamine borane, pyridine borane, morpholine borane, sodium borohydride, lithium aluminum hydride or hydrazine, said chemically reduced nuclei being more highly catalytic to the electroless deposition of a non-noble metal than are said light-generated metal nuclei, said layer additionally having a deposit of a non-noble metal selectively superimposed on said chemically reduced nuclei.
 9. A non-reversal imaging process comprising the sequential steps of a. exposing to a light image an element having a photosensitive layer comprising a composition capable, upon light exposure, of reducing compounds of metals more noble than silver to nuclei of said metals; b. providing in said photosensitive layer a compound of a metal more noble than silver, thereby producing light generated nuclei of said metal in light-exposed areas of said photographic element; c. treating said element with a solution of trimethylamine borane, triethylamine borane, dimethylamine borane, diethylamine borane, t-butylamine borane, pyridine borane, morpholine borane, sodium borohydride, lithium aluminum hydride or hydrazine to cause generation selectively in the non-light-exposed areas of said photographic element of chemically reduced nuclei of said metal; and d. plating non-noble metal differentially on said chemically reduced metal nuclei by electroless deposition.
 10. The process of claim 9 wherein said non-noble metal is cobalt, nickel or copper.
 11. A non-reversal imaging process comprising the subsequential steps of a. exposing to a light image a recording element having a photosensitive layer comprising a composition which upon light exposure is capable of producing nuclei of metal more noble than silver; b. treating said photosensitive layer with a solution of trimethylamine borane, triethylamine borane, dimethylamine borane, diethylamine borane, t-butylamine borane, pyridineborane, morpholine borane, sodium borohydride, lithium aluminum hydride, or hydrazine to cause generation selectively in non-light exposed areas of chemically reduced metal nuclei of said noble metal; and c. plating non-noble metal differentially on said chemically reduced metal nuclei by electroless deposition.
 12. A non-reversal imaging process comprising the sequential steps of a. exposing to a light image a recording element having a photosensitive layer comprising a composition which, upon light exposure, is capable of producing nuclei of platinum or palladium; b. treating said photosensitive layer with a solution of trimethylamine borane, triethylamine borane, dimethylamine borane, diethylamine borane, t-butylamine borane, pyridineborane, morpholine borane, sodium borohydride, lithium aluminum hydride, or hydrazine to cause generation selectively in non-light-exposed areas of chemically reduced nuclei of platinum or palladium; and c. plating non-noble metal differentially on said chemically reduced nuclei by electroless deposition.
 13. A non-reversal imaging process comprising the sequential steps of a. exposing to a light image a recording element having a photosensitive layer comprising a composition which upon light exposure is capable of producing nuclei of a metal more noble than silver, and b. treating said photosensitive layer with a solution of a non-noble metal compound and trimethylamine borane, triethylamine borane, dimethylamine borane, diethylamine borane, t-butylamine borane, pyridine borane, morpholine borane, sodium borohydride, or hydrazine to cause generation selectively in non-light-exposed areas of said photographic element of chemically reduced metal nuclei of said noble metal and to plate said non-noble metal differentially on said chemically reduced metal nuclei by electroless deposition.
 14. A non-reversal imaging process comprising the sequential steps of a. exposing to a light image a recording element comprising a photosensitive layer having a composition which upon light exposure is capable of generating nuclei of platinum or palladium; and b. treating said exposed photosensitive layer with an aqueous dimethylamine borane solution having, as a component, a compound of nickel or cobalt to cause development of chemically reduced nuclei of platinum or palladium in non-light exposed areas of said photosensitive layer and to deposit nickel or cobalt differentially on said chemically reduced nuclei by electroless deposition. 